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Objectives: We present the imaging findings of a newly identified lethal arteriopathy associated with a novel mutation in the gene encoding fibulin-4, occurring in a distinct community from southern India.Material and Methods: A total of 31 children from a distinct population subgroup who presented with characteristic arterial dilatation and tortuosity were studied. All children except one belonged to unrelated families from an ethno-religious group (Muslim) from the northern coastal belt of southern India. CT angiography was performed in 30 children and contrast MRA in one.Results: Impressive dilatation and elongation of ascending aorta, arch, descending aorta and main pulmonary arteries with characteristic narrowing of aortic isthmus were seen in all patients. Stenosis of arch branches, abdominal visceral branches and pulmonary artery branches was observed in 21 (68%), 23 (62.5%) and 20 (65%) patients respectively. Genetic studies revealed an identical mutation in exon 7 of the FBLN4 gene. On follow-up, 27 of them had died before the age of 3 years and only two children were alive after the age of 4 years.Conclusions: FBLN4-associated vasculopathy is a highly lethal disease characterized by severe aneurysmal dilatation of thoracic aorta, its branches and pulmonary arteries with stenoses at typical locations.Key Points: • Homozygous mutations in exon 7 of the FBLN4 gene can produce lethal vasculopathy. • Fibulin-4 is a critical determinant in human elastogenesis. • Imaging findings can give a clue to underlying connective tissue disorders. [ABSTRACT FROM AUTHOR]

Menkes disease is an X-linked disorder of copper metabolism caused by mutations in the ATP7A gene. Whereas most of the patients exhibit a severe classical form, about 9% of the patients exhibit a milder form of Menkes disease. The mildest form is called occipital horn syndrome (OHS). Mutations in the ATP7A gene can be identified in 95-98% of the Menkes disease patients by standard screening techniques. Investigation of RNA isolated from the fibroblasts of eleven patients with no identified mutations was performed, and revealed inclusion of new pseudo-exons into the ATP7A mRNA from three unrelated patients: two patients with OHS and one patient with classical Menkes disease. The pseudo-exons were inserted between exons 10 and 11, between exons 16 and 17 and between exons 14 and 15 in the three patients, as a result of deep intronic mutations. This is the first time the activation of pseudo-exons is demonstrated in the ATP7A gene, and it demonstrates the usefulness of RNA analysis, in terms of revealing disease-causing mutations in noncoding regions. The fact that three different mutations cause disease by the activation of pseudo-exon inclusion also indicates that in Menkes disease this is an important mechanism, which has hitherto been overlooked. [ABSTRACT FROM AUTHOR]

Fibulin-4 is a member of the fibulin family, a group of extracellular matrix proteins prominently expressed in medial layers of large veins and arteries. Involvement of the FBLN4 gene in cardiovascular pathology was shown in a murine model and in three patients affected with cutis laxa in association with systemic involvement. To elucidate the contribution of FBLN4 in human disease, we investigated two cohorts of patients. Direct sequencing of 17 patients with cutis laxa revealed no FBLN4 mutations. In a second group of 22 patients presenting with arterial tortuosity, stenosis and aneurysms, FBLN4 mutations were identified in three patients, two homozygous missense mutations (p.Glu126Lys and p.Ala397Thr) and compound heterozygosity for missense mutation p.Glu126Val and frameshift mutation c.577delC. Immunoblotting analysis showed a decreased amount of fibulin-4 protein in the fibroblast culture media of two patients, a finding sustained by diminished fibulin-4 in the extracellular matrix of the aortic wall on immunohistochemistry. pSmad2 and CTGF immunostaining of aortic and lung tissue revealed an increase in transforming growth factor (TGF)β signaling. This was confirmed by pSmad2 immunoblotting of fibroblast cultures. In conclusion, patients with recessive FBLN4 mutations are predominantly characterized by aortic aneurysms, arterial tortuosity and stenosis. This confirms the important role of fibulin-4 in vascular elastic fiber assembly. Furthermore, we provide the first evidence for the involvement of altered TGFβ signaling in the pathogenesis of FBLN4 mutations in humans. [ABSTRACT FROM AUTHOR]

Neurophysiological deficits could make patients with Ehlers–Danlos syndrome (EDS) type III (hypermobility type) more vulnerable to musculoskeletal problems, particularly to joint instability. The purpose of this study was to investigate whether joint position sense (JPS) and vibratory perception sense (VPS) in EDS type III patients in the knee and shoulder joints are impaired. Thirty-two female EDS type III patients as defined by the Villefranche criteria and 32 individually gender- and age-matched healthy control subjects were included in the study. Range of motion was determined using a goniometer, passive and active JPS were assessed with an isokinetic dynamometer system, and the VPS was measured by a biothesiometer. Daily physical activity was evaluated by the Baecke questionnaire. The EDS type III group showed significantly larger ranges of movement ( P < 0.05) and lower levels of sport physical activity (SPA) compared to the control group ( P = 0.023). Considering SPA as covariate, the EDS type III group demonstrated a significant impairment in knee joint reposition compared to the control group ( P = 0.018). No significant differences were found for shoulder JPS. The VPS was not significantly different in the EDS type III group compared to the control group. In addition, no significant correlation was found between JPS and VPS, neither at the knee nor at the shoulder joint. This is the first study examining proprioception deficits in EDS type III patients as defined by the Villefranche criteria. Further research on the neurophysiological dysfunctions and mechanisms in this pathologic entity is needed. [ABSTRACT FROM AUTHOR]

Mutations in ABCC6 cause pseudoxanthoma elasticum (PXE), a heritable disease that affects elastic fibers. Thus far, >200 mutations have been characterized by various PCR-based techniques (primarily direct sequencing), identifying up to 90% of PXE-causing alleles. This study wanted to assess the importance of deletions and insertions in the ABCC6 genomic region, which is known to have a high recombinational potential. To detect ABCC6 deletions/insertions, which can be missed by direct sequencing, multiplex ligation-dependent probe amplification (MLPA) was applied in PXE patients with an incomplete genotype. MLPA was performed in 35 PXE patients with at least one unidentified mutant allele after exonic sequencing and exclusion of the recurrent exon 23–29 deletion. Six multi-exon deletions and four single-exon deletions were detected. Using MLPA in addition to sequencing, we expanded the ABCC6 mutation spectrum with 9 novel deletions and characterized 25% of unidentified disease alleles. Our results further illustrate the instability of the ABCC6 genomic region and stress the importance of screening for deletions in the molecular diagnosis of PXE. [ABSTRACT FROM AUTHOR]

Osteoporotic fractures are an increasing cause of mortality and morbidity in ageing populations. A major risk determinant for these fractures is bone mineral density (BMD). Variation on BMD is thought, on the basis of twin and family studies, to be subject to a large amount of genetic variation and it has been hypothesised that this may be due to the influence of multiple genes. However, in families showing segregation of low or high BMD, single major genes have been shown to play a crucial role. We performed a genome-wide screen using 380 microsatellite markers in a single extended family (n=34) in which early-onset low spinal areal BMD segregates in an autosomal dominant-like fashion. A two-point linkage analysis was performed, revealing a maximum LOD score of 3.07 on 1p36.3 (D1S468), confirming results of previous linkage studies of BMD, while no other suggestive linkage peaks (LOD>2.2) were detected elsewhere in the genome. Microsatellite markers were subsequently genotyped for a ±6.9 Mb region surrounding D1S468. This revealed critical recombination events restricting the candidate region to 1.2 Mb and 19 genes. Sequencing analysis of the coding region of candidate genes WDR8 and EGFL3 revealed no mutations or disease-associated polymorphisms. Our results provide some evidence supporting the hypothesis that there are genetic determinants for spinal BMD on 1p36.3. Although no specific disease causing mutation has yet been found, the delineation of a relatively small candidate region in a single extended family opens perspectives to identify a major gene for spinal BMD.European Journal of Human Genetics (2008) 16, 970–976; doi:10.1038/ejhg.2008.31; published online 27 February 2008 [ABSTRACT FROM AUTHOR]

Arterial tortuosity syndrome (ATS) is an autosomal recessive disorder characterized by tortuosity, elongation, stenosis and aneurysm formation in the major arteries owing to disruption of elastic fibers in the medial layer of the arterial wall. Previously, we used homozygosity mapping to map a candidate locus in a 4.1-Mb region on chromosome 20q13.1 (ref. 2). Here, we narrowed the candidate region to 1.2 Mb containing seven genes. Mutations in one of these genes, SLC2A10, encoding the facilitative glucose transporter GLUT10, were identified in six ATS families. GLUT10 deficiency is associated with upregulation of the TGFβ pathway in the arterial wall, a finding also observed in Loeys-Dietz syndrome, in which aortic aneurysms associate with arterial tortuosity. The identification of a glucose transporter gene responsible for altered arterial morphogenesis is notable in light of the previously suggested link between GLUT10 and type 2 diabetes. Our data could provide new insight on the mechanisms causing microangiopathic changes associated with diabetes and suggest that therapeutic compounds intervening with TGFβ signaling represent a new treatment strategy. [ABSTRACT FROM AUTHOR]

Nephronophthisis (NPHP) is the most frequent genetic cause of chronic renal failure in children. Identification of four genes mutated in NPHP subtypes 1-4 (refs. 4-9) has linked the pathogenesis of NPHP to ciliary functions. Ten percent of affected individuals have retinitis pigmentosa, constituting the renal-retinal Senior-Loken syndrome (SLSN). Here we identify, by positional cloning, mutations in an evolutionarily conserved gene, IQCB1 (also called NPHP5), as the most frequent cause of SLSN. IQCB1 encodes an IQ-domain protein, nephrocystin-5. All individuals with IQCB1 mutations have retinitis pigmentosa. Hence, we examined the interaction of nephrocystin-5 with RPGR (retinitis pigmentosa GTPase regulator), which is expressed in photoreceptor cilia and associated with 10-20% of retinitis pigmentosa. We show that nephrocystin-5, RPGR and calmodulin can be coimmunoprecipitated from retinal extracts, and that these proteins localize to connecting cilia of photoreceptors and to primary cilia of renal epithelial cells. Our studies emphasize the central role of ciliary dysfunction in the pathogenesis of SLSN. [ABSTRACT FROM AUTHOR]

Merkel cell carcinoma (MCC) is a rare aggressive skin tumor which shares histopathological and genetic features with small-cell lung carcinoma (SCLC), both are of neuroendocrine origin. Comparable to SCLC, MCC cell lines are classified into two different biochemical subgroups designated as ‘Classic’ and ‘Variant’. With the aim to identify typical gene-expression signatures associated with these phenotypically different MCC cell lines subgroups and to search for differentially expressed genes between MCC and SCLC, we used cDNA arrays to profile 10 MCC cell lines and four SCLC cell lines. Using significance analysis of microarrays, we defined a set of 76 differentially expressed genes that allowed unequivocal identification of Classic and Variant MCC subgroups. We assume that the differential expression levels of some of these genes reflect, analogous to SCLC, the different biological and clinical properties of Classic and Variant MCC phenotypes. Therefore, they may serve as useful prognostic markers and potential targets for the development of new therapeutic interventions specific for each subgroup. Moreover, our analysis identified 17 powerful classifier genes capable of discriminating MCC from SCLC. Real-time quantitative RT-PCR analysis of these genes on 26 additional MCC and SCLC samples confirmed their diagnostic classification potential, opening opportunities for new investigations into these aggressive cancers.Oncogene (2004) 23, 2732-2742. doi:10.1038/sj.onc.1207421 Published online 2 February 2004 [ABSTRACT FROM AUTHOR]

Unlabelled: Neonatal Marfan syndrome, the most severe presentation of Marfan syndrome phenotypes (MIM 154700), is characterised mainly by joint contractures, arachnodactyly, loose skin, crumpled ears, severe atrioventricular valve dysfunction and pulmonary emphysema. Death usually occurs within the first 2 years of life from congestive heart failure. We describe here a newborn male with many typical characteristics of neonatal Marfan syndrome associated with a diaphragmatic eventration and a bilateral uretero-hydronephrosis with bladder dilatation. He died from cardiac failure due to severe tricuspid and mitral regurgitation at 62 h of age.Conclusion: Molecular analysis showed a heterozygous missense mutation at nucleotide 3165 (3165T>G) in exon 25 of the FBN1 gene, resulting in the substitution of cysteine for tryptophan (C1055W). [ABSTRACT FROM AUTHOR]

Pseudoxanthoma elasticum (PXE) is a heritable disorder characterized by calcification of elastic fibres in skin, arteries and retina that results in dermal lesions with associated laxity and loss of elasticity, arterial insufficiency and retinal haemorrhages leading to macular degeneration. PXE is usually found as a sporadic disorder, but examples of both autosomal recessive and autosomal dominant forms of PXE have been observed. Partial manifestations of the PXE phenotype have also been described in presumed carriers in PXE families. Linkage of both dominant and recessive forms of PXE to a 5-cM domain on chromosome 16p13.1 has been reported (refs 8,9). We have refined this locus to an 820-kb region containing 6 candidate genes. Here we report the exclusion of five of these genes and the identification of the first mutations responsible for the development of PXE in a gene encoding a protein associated with multidrug resistance (ABCC6). [ABSTRACT FROM AUTHOR]

Osteogenesis imperfecta (OI) is an autosomal dominant genetic disorder characterized by the presence of brittle bones and decreased bone mass (osteopenia), as a result of mutations in the genes that encode the chains of type I collagen, the major protein of bone. The clinical features of the disease range from death in the perinatal period to normal life span with minimal increase in fractures. The present report describes two polymerase chain reaction (PCR)-based assays allowing preimplantation genetic diagnosis (PGD) on the one hand for OI type I, the mildest form, and on the other hand for OI type IV, which is intermediate in severity between OI type I and OI type III. In the couple referred for PGD for OI type I, the female partner carried a 1-bp deletion in exon 43 of the COL1A1 gene, resulting in a premature stop codon in exon 46. The synthesis of too little type I procollagen results from such a non-functional or COL1A1 null allele. In the other couple, referred for PGD for OI type IV, the male partner carried a G to A substitution in exon 19 of the COL1A2 gene, which results in an abnormal gene product due to an αGly247 (GGT) to Ser (AGT) substitution (G247S). Both mutations result in the loss of a specific restriction enzyme recognition site and can therefore be detected by PCR amplification followed by restriction fragment analysis. PCR amplification of genomic DNA of the parents-to-be with one of the two primers fluorescently labelled, followed by automated laser fluorescence (ALF) gel electrophoresis of the amplified and restricted fragments, allowed a distinction between the healthy and affected genotypes. PCR on single Epstein-Barr-virus (EBV)-transformed lymphoblasts resulted in acceptable amplification efficiencies (87% and 85% for OI type I and OI type IV respectively) and the allele drop-out (ADO) rate was assessed at 11.5% and 11.1% for OI type I and OI type IV respectively. With research blastomeres, 100% amplification rates were obtained and no contamination was observed in the blank controls, which validated the tests for clinical application. Embryos obtained after intracytoplasmic sperm injection (ICSI) were evaluated for the presence of the normal genotype of the non-affected parent. For OI type I, two frozen-thawed ICSI-PGD cycles and two fresh ICSI-PGD cycles were carried out for the same couple. The transfer of two unaffected embryos in the last cycle resulted in a twin pregnancy. A twin pregnancy was also achieved in one clinical ICSI-PGD cycle for OI type IV. [ABSTRACT FROM AUTHOR]

We report a male neonate with craniofacial dysmorphic features, multiple congenital anomalies and an unusual form of chondrodysplasia punctata. Radiographic examination revealed punctate epiphyses and coronal clefting of the thoracic spine. The hand radiographs showed some similarities to the brachytelephalangic type of chondrodysplasia punctata. However, the disorder did not fit well with any known entity of chondrodysplasia punctata or other condition characterized by punctate epiphyses. [ABSTRACT FROM AUTHOR]

Three unrelated patients with congenital arthrogryposis and brittle bones, the main neonatal signs of Bruck syndrome, are presented. In infancy and early childhood recurrent fractures of ribs and long bones and persistent Wormian bones in the calvarium are reminiscent of osteogenesis imperfecta (OI) even with white sclerae, normal dental quality and normal hearing as important clinical negatives. The diagnosis was made before two years of age in two, and in adolescence in the third patient. The latter's radiologically documented long-term natural course reveals slow progressivity of osteopenia and growth deficiency, worsening tendon contractures and pterygia in addition to increasing spine and pelvis deformation. Mental development remains normal. Bruck syndrome is monogenic and probably due to homozygosity of an as yet unidentified gene. As no alteration in the collagens I and III is detected and molecular screening reveals no mutation in the COL1A1 and COL1A2 genes, the pathogenesis of this severe disorder of connective tissue remains largely unknown. [ABSTRACT FROM AUTHOR]

We took advantage of overlapping interstitial deletions at chromosome 8p11-p12 in two individuals with contiguous gene syndromes and defined an interval of roughly 540 kb associated with a dominant form of Kallmann syndrome, KAL2. We establish here that loss-of-function mutations in FGFR1underlie KAL2 whereas a gain-of-function mutation inFGFR1 has been shown to cause a form of craniosynostosis. Moreover, we suggest that the KAL1 gene product, the extracellular matrix protein anosmin-1, is involved in FGF signaling and propose that the gender difference in anosmin-1 dosage (becauseKAL1 partially escapes X inactivation) explains the higher prevalence of the disease in males. [ABSTRACT FROM AUTHOR]

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper. [ABSTRACT FROM AUTHOR]

The article presents a clinical utility gene card for Loeys-Dietz syndrome (TGFBR 1/2). It provides information on the characteristics of the disease including its name, mutation spectrum, and the estimated frequency of the disease. It also discusses TGFBR 1/2 testing which is the first test to perform in the indications of the disease.

This Clinical Utility Gene Card has been corrected since first published online on 7 April 2010. The Publisher was advised that seven author names had been omitted from the submitted article and these have now been incorporated as above. [ABSTRACT FROM AUTHOR]